Energy absorbers have often been customized or built in accordance with the requirements of the particular load conditions under which they were to perform. This is highly undesirable since building a shock absorber for each type of job is costly and time consuming. Further, customized shock absorbers are necessarily of many different sizes and there is generally no standardization among the indiviudal components thereof, thereby making maintenance expensive and difficult.
To overcome the above disadvantage, several energy absorbers have been commercially manufactured which permit the energy absorbing capability thereof to be adjusted in accordance with the expected load conditions, thereby permitting the shock absorber to be utilized in many different loading and environmental conditions. While many of these adjustable energy absorbers have been adaptable to a wide range of load conditions, nevertheless these energy absorbers have not been as widely utilized as the area of need for same might indicate since they have been relatively costly. Specifically, most known adjustable energy absorbers have utilized a complex adjustment structure which is both expensive to manufacture and difficult to use. More specifically, these known shock absorbers have required an excessive amount of precise, and hence costly machining.
Also, many of the known adjustable shock absorbers use concentric, inner and outer control sleeves which are relatively movable for controlling flow between two chambers. However, these sleeves must be machined with extremely precise tolerances and/or machined as a matched pair in order to permit proper fit and operation. This thus prevents random assembly of the parts, and hence substantially increases the cost of assembly.
Accordingly, it is an object of this invention to provide an improved energy absorber, particularly a hydraulic shock absorber, which overcomes the above-mentioned disadvantages. It is also an object of this invention to provide:
1. An improved energy absorber, as aforesaid, capable of being adjusted to absorb shock loads of varying amounts.
2. An energy absorber, as aforesaid, which is easily and precisely adjustable to vary the energy absorption characteristic thereof.
3. An energy absorber, as aforesaid, which permits the energy absorption characteristic to be precisely adjusted to a level compatible with the external load imposed thereon.
4. An energy absorber, as aforesaid, which is capable of absorbing progressively increasing amounts of energy so as to result in a substantially uniform, that is a substantially linear, stopping of a movable load.
5. An energy absorber, as aforesaid, which utilizes a control structure containing inner and outer concentric sleeves with one sleeve having an axially extending row of control openings therethrough, which sleeves have opposed conical surfaces thereon and are relatively axially movable to form a variable width flow control passage therebetween and thereby control the flow of fluid between two compartments so as to adjust the energy absorption capability of the shock absorber.
6. An energy absorber, as aforesaid, which permits the inner and outer control sleeves to be machined with normal tolerances while still permitting random selection of parts during assembly.
7. An energy absorber, as aforesaid, which is simple and compact in construction, economical to manufacture, efficient in operation, and simple to adjust.
Other objects and purposes of this inventon will be apparent to persons acquainted with apparatuses of this type upon reading the following specification and inspecting the accompanying drawings.